Volume Normalizer

Browser extension that normalizes video/audio element volume on selected high-noise websites.

Features

• Automatic volume normalization on supported websites
• Adjustable global target volume (0-100)
• Per-site enable/disable toggles
• Persistent settings using browser sync storage
• Works with dynamic page updates via MutationObserver

Supported Sites

• X / Twitter
• TikTok
• Instagram
• Facebook
• YouTube
• Twitch
• Reddit
• Dailymotion
• Vimeo
• Snapchat
• Pinterest
• Tumblr
• LinkedIn

Project Structure

• background.js: Persists settings outside the popup lifecycle
• content.js: Applies and re-applies normalized volume on media elements
• popup.html: Extension popup UI
• popup.js: Popup behavior and settings persistence
• manifest.json: Cross-browser MV3 source manifest
• scripts/build.js: Produces Chrome and Firefox build outputs in dist/
• package.json: Build and validation scripts

Build

1. Run npm install.
2. Run npm run build.
3. Use dist/chrome/ for Chromium browsers and dist/firefox/ for Firefox.

Installation (Chrome/Brave/Edge)

1. Run npm install.
2. Run npm run build.
3. Open chrome://extensions (or brave://extensions).
4. Enable Developer Mode.
5. Click Load unpacked.
6. Select dist/chrome/.

Installation (Firefox)

1. Run npm install.
2. Run npm run build.
3. Open about:debugging#/runtime/this-firefox.
4. Click Load Temporary Add-on.
5. Select dist/firefox/manifest.json.

Validation

• npm run check: Builds the extension and runs script syntax checks plus Firefox linting.

Development Notes

• Settings are stored in chrome.storage.sync.
• Content script uses exact domain/subdomain matching (no loose substring matching).
• Popup writes are proxied through the background script so final saves survive popup teardown.
• Build output strips BOMs and generates browser-specific manifests from the root source manifest.

License

MIT